JP2008135459A - Led light source and backlight system for liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an LED backlight in which low power consumption can be achieved, while ensuring high color rendering, high color reproducibility and high luminance. <P>SOLUTION: A single-chip system white LED of low power consumption, capable of ensuring luminance and a multichip system full-color LED ensuring high color rendering and high color reproducibility are combined, and these LEDs are appropriately arranged in an XY plane, thus obtaining an LED backlight in which low power consumption can be achieved, while ensuring high color rendering and high color reproducibility. In the LED light source, multichip full color LED is constituted by arranging a plurality of single color LEDs on one line in the Y direction, wherein full-color LEDs and single-chip white LEDs are arranged on a single line, in the X direction at regular intervals (d). For example, one white LED(W) is arranged in the XY plane, in between multichip full-color LEDs where three LEDs of RGB are arranged longitudinally, and this process is repeated periodically. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an LED light source using a light emitting diode and a backlight for a liquid crystal display device using the same.

  In a liquid crystal display, the liquid crystal itself does not self-emit, so it is necessary to illuminate the irradiation light from the outside using a backlight. Some have used (EL) as a light source, but conventionally, a backlight using a fluorescent lamp as a light source has been mainstream.

  However, since it is necessary to apply a high voltage (about 700 V) with a frequency of several tens of kHz to both ends of the lamp for lighting the fluorescent lamp, current leakage occurs through a minute stray capacitance, or a wire break or short circuit occurs. Etc. are likely to occur. In addition, white light obtained from fluorescent lamps is bluish, and in order to obtain high color reproducibility, it cannot be said that whiteness is sufficient, especially in cold cathode tubes, stable brightness and color rendering properties after power-on. It takes 10 minutes to get the light, and in addition, mercury is used in fluorescent lamps to facilitate the discharge in the tube. There were problems such as undesirable from the viewpoint of protection.

  On the other hand, when LED is used as a light source for backlight, it has a long life, is resistant to impact and does not easily break, is excellent in color purity, and is a low-voltage operating element, so it is easy to handle and safe. Excellent small size and light weight, stable color rendering and luminance light immediately after power-on, good linearity of light emission with respect to current value and fast response speed, etc. There are advantages, and research and development on LED backlights has been promoted. In particular, after practical use of blue LEDs, research and development for practical use has been accelerated taking advantage of the excellent color reproducibility and low environmental load of LEDs.

  However, when such an LED backlight is put to practical use, the conventional LED backlight is not always compatible with high color rendering, color reproducibility, and low power consumption while ensuring luminance. Has been pointed out (see, for example, Patent Document 1). In other words, a high-brightness LED backlight that is excellent in color rendering and color reproducibility consumes high power, but if it is intended to reduce power consumption, the color rendering and color reproducibility deteriorate. It is.

  By the way, in order to obtain white light, it is necessary to mix light of green (G), red (R), and blue (B) at a ratio of about 6 to 3: 1. The main reason is that the power-light conversion efficiency is different, and among them, the conversion efficiency of the green LED is particularly low, and the efficiency of the relatively high blue and red LEDs is not fully utilized.

  As another method for obtaining white light, there is a method using a white LED. A method of obtaining a pseudo white light by obtaining a yellow light by exciting a phosphor with a blue light and mixing the light with the original blue light is a current mainstream. In this method, it is possible to exceed the conversion efficiency (approximately 80 to 100 lm / W) of a fluorescent lamp, and it is possible to obtain a light source with very high power-light conversion efficiency, but the spectrum of white light is Unlike light obtained by mixing RGB colors, red and green are insufficient, and color rendering and color reproducibility are not good.

  In order to improve such a defect, a method of exciting a phosphor using a near-ultraviolet LED has been studied, and more reddish light can be obtained, but this method can also be obtained by mixing RGB. The reality is that color rendering and color reproducibility are still not good compared to light. This is a high-brightness LED backlight that uses the three primary colors of RGB and has excellent color rendering and color reproducibility. The power consumption is high, and when white LEDs are used to reduce power consumption, color rendering and color reproducibility are reduced. This is the basic reason for the problem.

Furthermore, a light source using an LED has a characteristic that a light emission spectrum changes depending on a current value flowing through the LED or an operating temperature. Conventionally, sensors for detecting a change in color and the detection thereof are used to correct this. It has been done to add means for correcting the color change according to the value. For this purpose, it is necessary to develop and install sensors and the like that are not originally required for the LED light source, control devices for controlling them, and means for controlling them (for example, control software). Necessary, and the price of the equipment was high, which was one factor hindering the spread.
JP 2006-079991 A

  The present invention has been made in view of such problems, and an object of the present invention is to provide an LED backlight capable of reducing power consumption while ensuring high color rendering, color reproducibility, and luminance. It is to be realized.

  In order to solve such a problem, the invention according to claim 1 is an LED light source, a multi-chip type full-color LED and a single chip, which are configured by arranging a plurality of single-color LEDs in a straight line in the Y direction. Type white LEDs are arranged at equal intervals in a straight line in the X direction, and an LED group consisting of one full color LED and n (n is a natural number other than 0) white LEDs is periodically arranged in the X direction. It is arranged.

  The invention according to claim 2 is an LED light source, wherein a multi-chip type full-color LED constituted by arranging a plurality of single-color LEDs in a straight line in the Y direction and a group of a plurality of single-chip type white LEDs are X It is characterized by being periodically arranged on a straight line at equal intervals in the direction.

  According to a third aspect of the present invention, in the LED light source according to the first or second aspect, the multi-chip full-color LED is composed of three LEDs that emit RGB colors.

  According to a fourth aspect of the present invention, in the LED light source according to the third aspect, the multi-chip type full-color LED is a first full-color LED in an RBG array or a second full-color LED in a GBR array. One full-color LED and second full-color LED are alternately arranged.

  The invention according to claim 5 is an LED light source, wherein a single color LED and a single chip type white LED are arranged in a straight line in the X direction at equal intervals, and one single color LED and n (n is The LED group composed of the white LEDs having a natural number other than 0) is periodically arranged in the X direction.

  According to a sixth aspect of the present invention, in the LED light source according to the fifth aspect, the monochromatic LED is an LED for color tone adjustment that emits one of RGB.

  A seventh aspect of the present invention is the LED light source control system according to any one of the first to sixth aspects, wherein the single-chip type is determined by a light emission luminance value of the LED light source based on luminance control information. An image processing control unit that generates a luminance control signal for determining a current value of the white LED, a current range determination unit that classifies a current value to be passed through the white LED determined based on the luminance control signal into a plurality of ranges, and A current control unit that stores current values to be sent to each of the plurality of LEDs constituting the multi-chip type full-color LED so that the color balance of the LED light source is in a preset range for each current range; and the current range determination unit A correction information selection unit that sends current value correction information for each of the plurality of LEDs to the current control unit based on a current range classification result of each of the plurality of LEDs. Characterized in that it comprises a brightness control unit for controlling the current, the flow into.

  According to an eighth aspect of the present invention, in the control system for an LED light source according to the seventh aspect, an external interface for adjusting luminance from the outside is further provided.

  A ninth aspect of the present invention is a liquid crystal display device comprising the backlight comprising the LED light source according to any one of the first to sixth aspects and the control system according to the seventh or eighth aspect.

  Thus, according to the present invention, a single-chip white LED capable of ensuring luminance with low power consumption, and a multi-chip (multi-color LED) full-color LED capable of ensuring high color rendering and color reproducibility. And these LEDs are appropriately arranged in the XY plane. Therefore, white LEDs share the luminance, and full-color LEDs share the color rendering and color reproducibility. And low power consumption backlight with good color and color reproducibility.

  In addition, the backlight (LED light source) for the liquid crystal display device of the present invention can set an arbitrary color temperature and a color balance, which is impossible with a conventional white LED alone, and a conventional LED backlight. It is possible to suppress fluctuations in color tone due to temperature, etc., which is a disadvantage of lights, and it is also possible to suppress changes in color due to current values, which was the biggest and common defect in multicolor LED combinations and white LED light sources. It is what.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The basic configuration of the present invention is to provide a backlight light source by combining and arranging full-color LEDs and white LEDs. Here, the full-color LED constituting the LED backlight of the present invention is of a multi-chip type, and a combination of LEDs capable of obtaining at least white by additive color mixing of three colors of RGB, or an LED with more color development. It may be a combination. For example, there may be a combination of a GaAlAs red LED, a GaP green LED, and an InGaN blue LED. Here, the “multi-chip type” full-color LED means an LED that obtains light of a desired color by additively mixing light of different wavelengths from a plurality of LEDs. It does not mean what is mounted on.

  In the following description, it is assumed that the full-color LED is a red (R) color LED, a green (G) color LED, and a blue (B) color LED, and thereby white light can be obtained. As will be described, the emission colors of these LEDs are not necessarily limited to three colors of red (R), green (G), and blue (B) in a strict sense. The full color LED used in the present invention may be a combination that can obtain white by additive color mixing, and a red (R) color system LED or a green (G) color can be combined. These are referred to as system LEDs and blue (B) color LEDs.

  The white LED constituting the LED backlight of the present invention is of a single chip type, and even if it is of a type that obtains white light using a blue LED and a phosphor, it is fluorescent using a near-ultraviolet LED. It may be of a type that excites the body, or may generate white light by other methods.

  When the backlight for a liquid crystal display device is composed only of the above-mentioned full-color LEDs, the power consumption increases if importance is placed on ensuring sufficient luminance as a backlight light source, and the luminance is insufficient when attempting to reduce power consumption. There is a problem of end. On the other hand, when the backlight is composed only of the above-described white LED, it is possible to obtain sufficient luminance, but it is difficult to satisfy the high color rendering and color reproducibility required for the liquid crystal display device. The color emitted by the white LED is fixed, and it is very difficult to change the color temperature etc. from the outside. Furthermore, color shift occurs due to fluctuations in the emission spectrum due to the operating conditions (ambient temperature and current value) of the white LED. There was also a serious problem of endangering.

  In addition to these problems, there is a problem of large luminance variations in LED backlights, and the emission spectrum of LEDs changes depending on the element temperature and the value of current flowing through the LEDs, resulting in “color shift”. There is also a problem that the color balance of the backlight is lost.

  Therefore, in the present invention, a single chip type white LED capable of ensuring luminance with low power consumption and a multichip type full color LED capable of ensuring high color rendering and color reproducibility are combined, and these LEDs are combined. An LED backlight that realizes both high color rendering and color reproducibility and low power consumption while ensuring luminance is realized by appropriately arranging in the XY plane.

  1A to 1C are diagrams for explaining an arrangement example of full-color LEDs (RGB LEDs) and white LEDs of a backlight according to the present invention. As shown in these figures, the multi-chip type full color LED is configured by arranging a plurality of single color LEDs in a straight line in the Y direction, and the full color LED and the single chip type white LED are in a straight line in the X direction. Are arranged at equal intervals (d).

  In the arrangement of FIG. 1A, one white LED (W) is arranged between multi-chip type full color LEDs in which three RGB LEDs are vertically arranged in the XY plane, and this is repeated periodically. It is said. In the arrangement of FIG. 1B, two white LEDs (W) are arranged in parallel between multi-chip type full color LEDs in which three RGB LEDs are vertically arranged. Three or more white LEDs (W) may be arranged in parallel between the multi-chip type full color LEDs. That is, an LED light source is configured by an LED group including one full-color LED and n (n is a natural number other than 0) white LEDs periodically arranged in the X direction.

  Further, in the arrangement of FIG. 1C, four white LEDs (W) are arranged one by one between multi-chip type full-color LEDs in which three RGB LEDs are vertically arranged, and these are adjacent to each other. Arranged by shifting between arrays. That is, a group of multi-chip type full color LEDs configured by arranging a plurality of single color LEDs in a straight line in the Y direction and a group of a plurality of single chip type white LEDs are periodically arranged on the straight line at equal intervals in the X direction. An LED light source is configured. Various LED arrangements other than those shown in FIGS. 1A to 1C are possible.

  In the LED arrangement examples shown in these figures, the arrangement of the three LEDs in the multi-chip type full-color LED is the first arrangement of RBG or the second arrangement of GBR from the upper direction in the figure. Two arrangements are repeated alternately.

  As a modification of the combination arrangement of the full color LED and the white LED as shown in FIGS. 1A to 1C, the white LED (W) is used as a basic light source of the backlight as shown in FIG. An RGB LED may be arranged as an accompanying light source for adjusting the color tone of the light from the LED. In the case of this configuration, it is not necessary to provide any LED of the three colors of RGB as an associated light source. In the example shown in FIG. 2, between two white LEDs arranged in parallel, Green LEDs (G) and red LEDs (R) are alternately arranged.

  If white light is to be obtained by additive color mixing using red LEDs, green LEDs, and blue LEDs to ensure high color rendering and color reproducibility, the total power consumption as a full color LED must increase. Absent. On the other hand, when a white LED is used, white light can be obtained alone, so that power consumption can be reduced in principle. However, it is generally difficult to ensure sufficient color rendering and color reproducibility. On the other hand, when a backlight is composed of a combination of a full color LED and a white LED, a backlight having both the advantages of a full color LED and the advantages of a white LED can be obtained, compared to a conventional LED backlight. It is a high-intensity light source with significantly reduced power consumption, and can achieve a backlight with excellent color rendering and color reproducibility.

  When a light source is formed by combining a full color LED and a white LED as in the present invention, the ratio of the “brightness variation” of the full color LED to the “brightness variation” of the entire backlight is small due to the high luminance of the white LED. Compared with the case where the backlight is configured by only full-color LEDs, it is possible to set a wider allowable range of “brightness variation” of each of the RGB LEDs. Further, as shown in FIG. 1B and FIG. 1C, if the arrangement ratio of the white LEDs to the full color LEDs is increased, the “brightness variation” of the entire backlight light of the “brightness variation” of each white LED is reduced. Since the occupying ratio is small, the allowable range of “brightness variation” of each white LED can be set widely.

  In addition, if the current that flows through the RGB LEDs that make up a full-color LED is controlled appropriately, even if the color balance of white light that occurs according to the element temperature and current value of the white LED is lost, it is adjusted. It becomes possible to do.

  The above-described technical advantage is that the backlight having the LED arrangement as shown in FIG. 2, that is, the backlight having a configuration in which white LEDs are used as the basic light source of the backlight and at least one of the RGB LEDs is arranged as the accompanying light source. Can be obtained similarly.

  FIG. 3 is a block diagram for explaining a configuration example (backlight control example) of a liquid crystal display device having a backlight according to the present invention, and FIG. 4 is a flowchart for explaining a flow of signal processing for backlight control. It is.

  When the encoded image information for one screen is input, the image processing control unit (11) performs decoding processing to generate image data (S101), and the liquid crystal on the liquid crystal display panel side based on the image data A drive signal (RGB signal) and a luminance control signal (backlight signal) on the backlight side are generated (S102). Here, the liquid crystal drive signal (RGB signal) is a signal for controlling the RGB liquid crystal shutters of each pixel on the liquid crystal display panel side, and the luminance control signal (backlight signal) is the brightness of the image to be displayed. This is a signal for controlling the brightness of each of the white LED and the full color LED necessary for setting the brightness of the backlight to be controlled in accordance with the brightness (the brightness of the backlight light) to a predetermined value.

  The liquid crystal drive signal (RGB signal) and the luminance control signal (backlight signal) are transmitted to the image synchronization / data transmission control unit (12), and the RGB signal and the backlight signal are transmitted by the image synchronization / data transmission control unit (12). In synchronization with the display timing of the image to be displayed on the liquid crystal display panel (S103), the RGB signal and the backlight signal are transmitted to the liquid crystal display panel (13) and the backlight luminance instruction unit (14), respectively (S104).

  Based on the backlight signal, the backlight luminance instruction unit (14) generates an LED luminance control signal for luminance control so that the luminance of the backlight light becomes a predetermined luminance, and this signal is subjected to the total luminance control. It is sent to the current range determination unit (16) together with the DA converter (15).

  The total brightness control DA converter (15) uses a signal used as a reference for controlling the brightness of each of the white, red, green and blue LEDs based on the LED brightness signal, and the brightness control DA converter (19W) associated with each of the white, red, green and blue. , 19R, 19G, 19B) (S105). Further, the current range determination unit (16) determines in which range the current value to be passed through the white LED determined based on the above-described LED brightness control signal is present (S106). Here, although the value of current flowing through the LED and the luminance are in a proportional relationship, non-linearity is also inherent, and therefore, here, it is described that the luminance of the white LED is also corrected.

  The current control register unit (17W, 17R, 17G, 17B) is a storage unit provided in association with each of white, red, green, and blue LEDs, and light output as a backlight for each current range determination value. Is stored so that the current value flowing through each of the white, red, green, and blue LEDs is corrected so that the color balance of the color is in a preset range, and the correction information is associated with each of the white, red, green, and blue LEDs. The data is sent to the brightness control DA converter (19W, 19R, 19G, 19B) associated with the LED of each color via the selection unit (18W, 18R, 18G, 18B) (S107).

  The current range determination unit (16) has a function (for example, a table) for classifying the current value passed through the white LED into a plurality of levels (current value range), and is determined based on the LED luminance control signal. In which current value range is determined (S106). Note that the brightness of the backlight is determined according to the current flowing through each of the white, red, green, and blue LEDs, and the LEDs constituting the backlight are many white LEDs. Therefore, the brightness of the backlight is determined by the current value flowing through the white LED. Therefore, the “current value range” is substantially the same as the “luminance range” of the white LED.

  For example, the current range determination unit (16) classifies the white LED brightness into 10 levels (levels 1 to 10) of 10% in the minimum to maximum brightness range, and the “current range” corresponding to each “brightness range”. A table for classification into “value range” is stored. Then, if the current value associated with the white LED corresponds to, for example, 46% luminance, a determination to classify into a current value range corresponding to the luminance range 41% to 50% (for example, determination to level 5) is executed. The result is sent to the selection unit (18W, 18R, 18G, 18B) (S108).

  The current control register section (17W, 17R, 17G, 17B) stores information (for example, a table) for setting the backlight color balance within a preset range. The emission spectrum of the LED changes according to the element temperature and the value of the current flowing through the LED, resulting in a “color shift”. Therefore, if the brightness control of each of the white, red, green, and blue LEDs is performed based on only the brightness control signal without correcting such “color shift” of the LED emission spectrum, the backlight is caused by the “color shift”. As a result, the color balance is lost. In order to suppress such a change in color balance within a preset range, correction is made to each of the red, green and blue LED luminance signals, and the “color shift” of the LED light source is manifested as a significant disruption of the color balance of the backlight light. You don't have to make it. In addition, although the current value flowing through the LED and the luminance are in a proportional relationship, nonlinearity is also inherent, so here it is possible to control the luminance of the white LED more accurately by correcting the luminance of the white LED. It is said. The information stored in the current control register unit (17W, 17R, 17G, 17B) is such current value correction information.

  If this current value correction information is used, when a current value determined based on the LED brightness control signal input from the backlight brightness instruction section (14) is directly passed to each of the white, red, green and blue LEDs, at least one of these LEDs will be displayed. If this causes a “color shift” and this “color shift” breaks the color balance of the backlight light, the current flowing to the LED is controlled, and even if the “color shift” occurs, the backlight The light color balance change is corrected so as to be within a predetermined range. Such “color misregistration” can also occur in all white, red, green, and blue LEDs. Therefore, the current control register section (17W, 17R, 17G, and 17B) includes a current value range that flows through the white LED. In addition, current value correction information for each LED associated with the current range is set.

  The current value range determination result of the white LED is output from the current range determination unit (16) to the selection unit (18W, 18R, 18G, 18B), and the selection unit (18W, 18R, 18G, 18B) Based on the current control register unit (17W, 17R, 17G, 17B), necessary current value correction information is selected (S109), and the current value correction information selected for each LED is associated with each of white, red, green, and blue The brightness control DA converter (19W, 19R, 19G, 19B) is sent (S110).

  The brightness control DA converter (19W, 19R, 19G, 19B) is used as a reference when controlling the brightness of the LED transmitted from the all brightness control DA converter (15) based on the current value correction information for each LED described above. The signal to be used is corrected, the luminance signal for each color LED after correction is converted into an analog signal, which is sent to the current control circuit section (20) (S110), where it is converted into a current value to be passed through each LED. That is, the brightness control DA converter (19W, 19R, 19G, 19B) uses the current value determined from the signal used as a reference when controlling the brightness of the LED transmitted from the all brightness control DA converter (15) as the reference current value. The voltage corresponding to the correction content of the current value selected by the selection unit (18R, 18G, 18B) is output (S111).

  For example, when the selection unit (18W, 18R, 18G, 18B) instructs correction of the current value range, it is used as a reference for controlling the luminance of the LED transmitted from the full luminance control DA converter (15). If the current value itself determined from the signal is output as a set value (reference voltage) for flowing to each LED and indicates that correction is required, the set value (correction voltage) corresponding to the corrected current value range ) Is output. It should be noted that a manual luminance adjustment signal can be input to the full luminance control DA converter (15) from the outside via an external interface (21) and a manual luminance control DA converter (22).

  If such current control is performed, each of the RGB LEDs constituting the full-color LED emits light so that the color balance is within a predetermined range for each operating current range. Even if the operating current of the LED changes and a “color shift” occurs, the variation in the color balance of the backlight light can be kept within a preset range.

  The present invention has been described with reference to the embodiments. However, the above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of the above-described embodiments are within the scope of the present invention, and various other embodiments are possible within the scope of the present invention. For example, an LED used as a backlight is not necessarily a three-color LED of a red (R) LED, a green (G) LED, and a blue (B) LED, and a white LED is obtained by mixing colors. May be any combination of LEDs (red (R) color system LED, green (G) color system LED, and blue (B) color system LED), and further, a white LED and any one of these LEDs It is good also as a combination. Further, the correction instruction of the current value range of the selection unit may be performed only for RGB. In this case, the color balance can be controlled more easily and the amount of hardware required is reduced, so that the device price can be further reduced.

  According to the present invention, it is possible to realize an LED backlight capable of reducing power consumption while ensuring high color rendering, color reproducibility, and luminance.

It is a figure for demonstrating the example of arrangement | positioning of full color LED (each LED of RGB) and white LED of the backlight of this invention. It is a figure for demonstrating the other example of arrangement | positioning of LED of the backlight of this invention. It is a block diagram for demonstrating the structural example (backlight control example) of the liquid crystal display device provided with the backlight of this invention. It is a flowchart for demonstrating the flow of the signal processing for backlight control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Image processing control part 12 Image synchronization and data transmission control part 13 Liquid crystal display panel 14 Backlight brightness instruction | indication part 15 Total brightness control DA converter 16 Current range determination part 17 Current control register part 18 Selection part 19 Brightness control DA converter 20 Current control Circuit part

Claims (9)

A multi-chip type full-color LED configured by arranging a plurality of single-color LEDs on a straight line in the Y direction and a single-chip type white LED are arranged on the straight line at equal intervals in the X direction. An LED light source, wherein a group of n (n is a natural number other than 0) white LED is periodically arranged in the X direction. A multi-chip type full color LED composed of a plurality of single color LEDs arranged in a straight line in the Y direction and a group of a plurality of single chip type white LEDs are periodically arranged on the straight line at equal intervals in the X direction. LED light source characterized by 3. The LED light source according to claim 1, wherein the multi-chip type full-color LED is composed of three LEDs that emit respective colors of R (red), G (green), and B (blue). The multichip type full-color LED is a first full-color LED in an RBG array or a second full-color LED in a GBR array, and the first full-color LED and the second full-color LED are alternately arranged. 3. The LED light source according to 3. A single color LED and a single chip type white LED are arranged at equal intervals in a straight line in the X direction, and an LED group consisting of one single color LED and n (n is a natural number other than 0) white LEDs is X. An LED light source, which is periodically arranged in a direction. The LED light source according to claim 5, wherein the single-color LED is an LED for color tone adjustment that emits one of RGB. The LED light source control system according to any one of claims 1 to 6,
An image processing control unit for generating a luminance control signal for determining a current value of the single-chip white LED determined by a light emission luminance value of the LED light source based on luminance control information;
A current range determination unit that classifies a current value flowing through the white LED determined based on the luminance control signal into a plurality of ranges;
A current control unit that stores current values to be sent to each of the plurality of LEDs constituting the multi-chip type full color LED so that the color balance of the LED light source is in a preset range for each current range;
A correction information selection unit that sends current value correction information for each of the plurality of LEDs to the current control unit based on a current range classification result of the current range determination unit;
A luminance control unit for controlling a current flowing through each of the plurality of LEDs;
An LED light source control system comprising: The LED light source control system according to claim 7, further comprising an external interface for adjusting brightness from the outside. A liquid crystal display device comprising the backlight comprising the LED light source according to any one of claims 1 to 6 and the control system according to claim 7 or 8.

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